Alkyl substituted aromatic sulfonates



April 12, 1949. q

M. HUNT ET AL ALKYL SUBSTITUTED AROIIA'I'IQ SULI'OKA'IBS 2 snoot sneet 1 Filed on. 15. 1947 FIGJ.

Detergent Concentration in FIGJI.

a a Q a 86 i 2 2523..- 32.235

Detergent Concentration in X aze-1 A rronnsY April 12,1949. M. HUNT ETAL ALKYL SUBSTITUTED AROIMTIC SULFONATES 2 Sheets-Sheet- 2' Filed 001;. 15, 1947 Flam.

Doiorqont Concentration In QFIGJI.

' zzvmvrons Dcfcrqcnt Concentroflon m% v JMDISON HUNT VIK TOR W INMAY MARIO FRANGESO SARFO? IQR Patented Apr. 12, 1949 ALKYL sons'rrro'rnnsnoMa'rro SULFONATES Madison Hunt, Claymont, Del., Viktor Weinmayr, Pitman, N. J and Mario Francesco Sal-tori, Wilmington, Del., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware Application October 15, 1941, Serial No. 780,096

6 Claims. (Cl. 260-505) This invention deals with a group of alkylaromatic sulfonic acids andtheir salts useful as surface active agents, particularly as detergents and wetting agents.

It is an object of this invention to provide new detergent compounds of superior detergent power in hard water.

The use of alkylated aromatic sulfonic acids as detergents as a general proposition is well known. Both sulfonated naphthalene and benzene derivatives have been indicated in the art, and the length of the alkyl chain has been varied from as low as 3 carbon atoms to as high as 20 carbon atoms, both straight-chain and branched-chain radicals being often employed.

- We have now found that the limited group of compounds having the particular structure defined hereinbelow possesses outstanding qualities as detergents, being superior to hitherto described compounds as regards detergent power at low concentrations in' hard water.

The novel compounds embraced in this invenv wherein R is a straight-chain, saturated aliphatic hydrocarbon radical of 8 to 11 carbon atoms, R designates a methyl or ethyl radical, while X represents the sulfonic acid radical or a salt thereof.

This invention embraces the above compounds in free acid form as well as in the form of watersoluble salts thereof, as obtained for instance by neutralizing the free acid with inorganic or organicbases. For the purpose of this invention, the term "water-soluble shall be construed as meaning that the compound concerned is soluble 2 in water to an extent of at least 0.2% by weight.

The products of this invention are prepared by sulfonating the corresponding hydrocarbon with oleum and, if desired, neutralizing the sulf onic acid thus formed with an alkali-metal hydroxide, an alkaline-earth hydroxide, or any other alkaline agents such as primary, secondary or tertiary amines or quaternary nitrogenous bases. The alkylaromatic compounds themselves may be prepared by. any suitable synthesis, such as the Friedel-Crafts reaction or reactions based on a Grignard synthesis. These methods of preparation are illustrated in the following examples, which however are given merely for illustrative purposes, without any intent to limit the invention thereby.

The annexed drawing represents graphically I thedata obtained in our tests on the novel compounds and reported in the tables hereinbelow.

EXAMPLE 1.2-(P-ME'rHYL PHEnYL -Donncmn A. Preparation of the hydrocarbon tion mixture is then poured slowly into 550 parts of water, and the upper organic layer is separated and washed, first with water and then with 5% sodium carbonate solution. After removal of the excess toluene by distillation, the product is distilled under vacuum. 22.4 parts of a product boiling at 130 C. at 2 mm. pressure are thus obtained. The product gives a refractive index of no"=1.4855 and a density of B. Sulfonation To 15 parts of the above product, 27 parts of 20% oleum' are added slowly with cooling and agitation so as to hold the temperature at 20-30 C. After all of the oleum has been added, the temperature of the reaction mixture is raised to 45- 50 C. and held at this temperature for one-half hour. The product is poured into parts of water, and 10 parts of alcohol are added in order to obtain a homogeneous solution. The mixture is neutralized to a pH of 7-8 with 20% sodium hydroxide solution. The mixture is drum-dried to yield 50 parts of a product containing about 40% active ingredient and 60% sodium sulfate. The active ingredient may be isolated in a pure state by extraction of the 40% product with hot alcohol.

Instead of sodium hydroxide in the above example the corresponding equivalent weight of any other hydroxide or base which leads to a water-soluble suli'onate may be used, for instance potassium hydroxide, calcium hydroxide, magnesium hydroxide, ammonia, monomethylamine, dimethylamine, trimethylamine, tetramethylammonium hydroxide, the corresponding ethyl amines, the various ethanolamines (mono-, diand tri-), etc.

ExAurLr: 2.-PREPARATION AND SULFONATION or 2- (r-MnrnYL-Pnrnn) -DECANE To a mixture of 50 parts of toluene and 15 parts of anhydrous hydrogen fluoride are added 10 parts of decene-l at a temperature of 05 C. After addition is complete, the mixture is stirred at 0-10 C. for eighteen hours. The mixture is -lected. The product has a refractive index of poured slowly into 300 parts of ice-water and the upper organic layer is separated. The product is washed with water and finally with 5% sodium carbonate solution. After removal of the excess toluene by distillation, the product is distilled in vacuum. The fraction boiling at 108 C. at 3 mm. is collected. A sample of this product gave a refractive index of nn==1.4871 and a density of Analysis: Calculated for Ci-zHaa, C=87.8, H=12.2. Found, C=86.1, H=12.1.

The above product is sulionated and optionally neutralized as described in Example 1. After drum-drying, a product of light cream color is obtained. This material is soluble in water to give a foaming solution.

ExAMPLz 3.PREPARATION AND Surromrrorr or 2- (P-ETHYL-PHENYL) -DODECANEGRIGNARD SYN- rnnsrs To a suspension of 15 parts of magnesium in 450 parts of anhydrous ether 132 parts of n-decyl bromide are added dropwise, with stirring, at reflux temperature. The rate of addition is adjusted so that the heat of reaction maintains the refluxing of the ether. After addition of the bromide is complete, the mixture is refluxed for one hour. A solution of 74 parts of the p-ethylacetophenone (prepared according to A. Klages, Ber., 32, 1558 (1899)) in 150 parts of anhydrous ether is added over a period of one hour, and the mixture is refluxed an additional half hour. The

reaction mixture is poured into ice water and acidified with hydrochloric acid. The upper layer is separated, extracted with 5% sodium carbon- Analysis calculated for C2oHa4, C=8 .6, H=12.5. Found: C=87.'79, H=13.33.

The above product is sulfonated and neutralized with NaOH as described in Example 1, to yield a detergent mixture containing approximately 40% active ingredient and 60% sodium sulfate.

EVALUATION or ran Pnonucrs The evaluation of the above products for wetting power has been carried out as described in the AATC (American Association of Textile Chemists and Colorists) Year Book for 1946,'page 230. The wetting power is gauged by the concentration in grams of active ingredient per liter oi solution necessary to wet in 25 seconds. In Table V below, this concentration is designated as the standard wetting concentration. For detergent evaluation, the method described by O. C. Bacon, American Dyestuif Reporter, vol. 34, pages P556-P561, has been used; The results are expressed in tabular form using the percent reflectance of light from the surface of the soiled fabric relative to the reflectance of magnesium oxide as a measure of "brightness." The detergent is tested at five difierent concentrations.

Using these methods, the products of this invention show outstanding detergency at the low detergent concentrations in hard water. This is a real advantage even though at high concentration, other closely related structures may have approximately equal activity. At the same time, the wetting speed of the products of this invention is sufficiently high for practical purposes, and a significant improvement is noted over the products in which the phenyl group is attached to the 1-position on the aliphatic chain.

The following table illustrates the superiority of the p-methylphenyl compounds over the corresponding unsubstituted phenyl compounds at low detergent concentrations in hard water. The numerical values represent the percent reflectance of the washed fabric relative to magnesium oxide as The water employed in these tests contained 360 parts per million of alkaline earth chlorides calculated as calcium carbonate.

TABLnI Detergent Concentration a 'inpercent 3 po nd [5 0 |0.05!0.10 0.15\0.260.35 (0) Sodium sulfonate oiZ-(p-methyl- I phenyl)-dodecane 36 47 49 50 50 50 (b) Sodium sulfonate oi Z-(p-ethylphenyl)-undecane 30 44 46 48 46 47 (c) Sodium sulfonate of 2-(p-ethylphenyl)-dodecane 36 47 50 50 50 50 (41) Sodium sulfonate of 2-phenyldecane 36 36 43 44 45 45 (0) Sodium sulfonate oi Z-phenyldodecane 36 37 46 49 50 50 The above data are reproduced graphically in Figure I, wherein the individual-curves have been 5 be noted that curves d and e drop considerabl below curves a, b and c in the region of low concentrations. I r

The effect of the para methyl group in enhancing detergency is not observed when methyl groups are introduced into positionsother than the para position. This is shown in Table II.

TABLE II in percent Compound Graph No.

Sodium sullonate oi 2-(p-methylphenyl)-dodecane Sodium suii'onate of 2-(2,5-dimethylphenyD-dodecane TABLE III 2 Detergent Concentration in percent '5, Compound (5 O 0.050.100.150.250.35

(a) Sodium sulfonate 0i 2-(p-methy1- phenyl)-dodecane 36 47 49 50 50 5O 1 (g) Sodium sulionate of toluene a1- kylated with polymerized propylene (C 36 36 37 42 44 47 (h) Sodium sulfonate of benzene a1- kylated with polymerized propylene (Cu) 36 38 46 50 52 52 The graphs pertaining to this table are given in Figure III, the individual curves being marked to correspond.

The polymerized propylene (C12) which gives a good detergent when alkylated onto benzene, is a mixture of highly branched twelve carbon chains. However, the product from polypropylene (C12) and benzene is much inferior at low detergent concentrations in hard water to the products of this invention. The toluene derivative is a very poor detergent.

The introduction of groups larger than ethyl into the para position on the benzene-ring does not give the enhancement of detergency noted with methyl or ethyl groups. This is illustrated in the following table:

. TABLE IV 2 Detergent Concentration n inpercent g. Compound :3 0 0.050.100.150.250.35

(0) Sodium sulionate of Z-(D-methylphenylydodecane 36 47 49 50 50 50 (1:) Sodium sulfonate of 2-(p-isopropylphenyD-dodecane 36 36 36 37 43 46 (1) Sodium sulfonate oi 2(p-isopro- I pylphenyD-decane 36, 37 39 50 50 50 For the corresponding curves, see Figure IV.

The location of the p-tolyl radical in the 2- position, of the alkane is particularly advantageous, because these compounds are readily Detergent Concentration available by alkylation of terminally unsaturated olefines. In addition, the wetting speed of compounds with the aryl group attached to the 2- position is much better than the corresponding It will be understood that many variations are possible in the methods of synthesizing the novel compounds and in the choice of base for neutralizing the sulfonic acid group. Apart from the last-mentioned freedom of variation, however, the number of sulfonic acids falling within the scope of this invention is limited and is represented in fact by the following 8 compounds:

2- (p-methylphenyl) -decanesulfonic acid 2- (p-methylphenyl) -undecanesulfonic acid 2- (p-methylphenyl) -dodecanesulfonic acid Z-(p-methylphenyl) -tridecanesulfonic acid 2- (p-ethylphenyl) -decanesulfonic acid 2- (p-ethylphenyl) -undecanesulfonic acid Z-(p-ethylphenyl) -dodecanesu1fonic acid 2- (p-ethylphenyl) -tridecanesulfonic acid The products of this invention are useful as surface active agents, particularly as detergents and wetting agents. The products show unusually high detergency at low concentrations in hard water. It is expected thatin actual practice, the concentrations employed will generally fall within the limits indicated in the above tables.

We claim as our invention:

1. As new compounds, the monosulfonic acids and water-soluble monosulfonic acid salts of the hydrocarbons included in the following formula wherein R is a straight-chained, saturated, aliphatic hydrocarbon radical of not less than 8 and not more than 11 carbon atoms, while R" is an alkyl radical of less than three carbon atoms.

2. The dialkyl-benzene-sulfonates of the general formula wherein M is an alkali-metal, R is a straight- 7 6. A detergent composition comprising as active ingredient a. compound consisting of a normal alkane of not less than 10 and not more than 13 carbon atoms bearing in the z-carbon atom a.

monosulfonated benzene radical which in turn 5 bears in p-position an aliwl radical selected from the group consisting of methyl and ethyl.

MADISON HUNT. VIKTOR WEINMAYR. MARIO FRANCESCO SARTORI.

REFERENCES CITED The following references are of record in the tile of this patent:

8 UNITED STATES PA'I'ENTS Number suter: "Organic Chemistry of Suliur,"

m 8: Sons, Inc..

Name Date Kyrides June 6, 1939 Flett Apr. 30, 1940 Brandt June 3, 1941 OTHER REFERENCES Wiley New York, New York, 1944, page 206. 

